[en] A software package for sequence scheduling and control in nuclear power plant construction has been developed and successfully applied at the Stendal site. The dialogue-oriented package written for business and personal computers enables the management to plan and control better the execution of the project

[en] The weight function method is described to analyze the crack growth behavior in functionally graded materials and in particular materials with a rising crack growth resistance curve. Further, failure of graded thermal barrier coatings (TBCs) under cyclic surface heating by laser irradiation is modeled on the basis of fracture mechanics. The damage of both graded and non-graded TBCs is found to develop in several distinct stages: vertical cracking→delamination→blistering→spalling. This sequence can be understood as an effect of progressive shrinkage due to sintering and high-temperature creep during thermal cycling, which increases the energy-release rate for vertical cracks which subsequently turn into delamination cracks. The results of finite element modeling, taking into account the TBC damage mechanisms, are compatible with experimental data. An increase of interface fracture toughness due to grading and a decrease due to ageing have been measured in a four-point bending test modified by a stiffening layer. Correlation with the damage observed in cyclic heating is discussed. It is explained in which way grading is able to reduce the damage

[en] The formation of creep pores at grain boundaries as a result of stress concentration in slip processes is investigated by means of instationary nucleation theory. The development of the pore size distribution is numerically calculated. The critical stress is assessed above which persistently growing micropores are formed. It agrees better with experiment than those derived from stationary or quasi-stationary models. (orig.)